The field of this invention is wrapping machines for use in manufacturing layered vessels, particularly of the type for use in constructing large diameter layered vessels.
Conventional types of wrapping machines typically are of a two-strap or cable variety, such as that pictured in U.S. Pat. No. 2,480,369. Such conventional two-cable type machines are adequate for wrapping relatively small diameter vessels. However, layered vessels that exceed eight feet in diameter are typically difficult to wrap using such machines. Not only are the cables difficult to move into a working position and align due to such cables being flexible and being typically suspended from a supporting structure but also the cables are required to be positioned about the vessel in a spiral fashion. The spiral action of each of such individual cables produces an eccentric loading on the vessel and therefore, two cables must be used, each with a spiral in opposing directions, to counteract the eccentric loading of the layered vessel. Further, the prior art cables typically are supported on a massive structure because the contraction of such cables frequently results in lifting the layered vessel, hence requiring a large supporting structure to bear the weight of the layered vessel and a portion of the wrapping machine. Inasmuch as large wrapping machines must be moved along the length of the layered vessel as the wrapping process progresses, movement, due to the mass of the structure, is slow and cumbersome.